The present invention relates in general to metal cutting equipment, and in particular to a new and useful tube cutter which utilizes an electrode rotating in the tube for the purpose of cutting the tube.
An internal tube cutter is known from U.S. Pat. No. 4,476,368. The cutter of this patent is a heavy apparatus which includes two drive mechanisms. One drive mechanism rotates a shaft which carries an electrode. The electrode makes intermittent contact with the inner circumference of the tube. The second drive mechanism rotates a sleeve which is engaged around the electrode shaft for guiding the areas of contact between the electrode and the inner circumference of the tube. It is known to power such an electrode using ac power with the rotation being timed to correspond to positive portions of the ac power wave, during the epicyclic rotation of the electrode.
Such known tube cutters in addition to being heavy and complex, require small components which may break and which are difficult to replace. The device also suffered from the leakage of water coolant which is required for its operation. The need for water tight seals also made the replacement of broken parts more difficult. Also, due to the intermittent contact between the electrode and the inner circumference of the tube, a relatively large amount of electrical power is needed to erode the tube material.